1. Field of the Invention
This invention relates to an apparatus for performing separation of a solid-liquid mixture fluid (original fluid) of high density including fine solid particles, and more particularly to a solid-liquid separator including a device for effectively scraping a solid component, i.e. cake, layered on a filtering surface of a filtering member to thereby separate such liquid component.
2. Description of the Prior Art
Waste cutting oil or waste grinding liquid discharged from a cutting machine or grinding machine often contains a solid mixture consisting of many fine solid particles having a high density. For this reason, a conventional filtering device is not practical for use in filtering such waste oil or waste liquid but there are many kinds of solid-liquid separators or separating apparatus which are utilized for this purpose. The solid-liquid separators tend to be bulky and complicated, consequently each cutting machine or grinding machine is not equipped with such a solid-liquid separator or separating apparatus, which is instead used alternatingly in one factory.
Usually, as a separator which is used with one machine, there includes a centrifugal separator, a separator operable by use of a magnetic force and a separator assembly which includes a filtering device. The separators of these types have, however, no sufficient filtering ability or treating ability with respect to the original fluid containing solid particles with a content of more than 1000 ppm. Particularly, the separators of these types are not sufficiently utilized for the separation of expensive cutting oil or grinding liquid to recover and reuse the same after it is once used, and the recovered liquid or fluid further contains fine solid particles with the content order of more than 100 ppm. Accordingly, a further precise filtering operation is required to reuse the waste oil or liquid.
In order to achieve the object described above, a rotary-type filtering machine, such as an Oliver filtering machine, is proposed in which the supply of the filtering material, the removal of the filtering liquid, the generation of filtered material, the cleaning thereof, the dehydration operation, and the disposal thereof are continuously performed while rotating the filtering surface of the filtering machine. The filtering surface is usually of a cylindrical shape and the filtering operation is performed under a vacuum condition. The rotary-type filtering machine, after setting of the operational conditions, can continuously perform the filtering cleaning, dehydration, and discharging processes, and is therefore widely used recently for the dehydration operation in the chemical industry for the lapping original liquid, a rutile in the cyanide process, the filtering operation of pulp, cement, mud or slip, starch, an asbestos and paper pulp. The filtering body of the rotary-type filtering machine is constructed by a drum comprising a wooden or metal cylindrical shell and a filtering cloth, in which arcuate chambers are defined on the outer peripheral surface of the drum and the lattice surface of each arcuate chamber is covered with a filtering cloth or fine wire gauze. Wire may be helically wound around the filtering cloth or the gauze as the occasion demands. The respective arcuate chambers can perform the independent filtering operation with each other and several suction pipes extend from the respective chambers towards the axis of the cylindrical drum. A filtering cloth or a sintered material is used as a filtering member of the filtering body, so that the filtering operation cannot be performed very precisely, and moreover the structure thereof is made complicated. The maintenance, for instance, the exchange of the filtering cloth, is not easily carried out. In addition, since the filtering member is not integrally constructed and the preparations of the lattice and the wire gauze are required, it is considerably difficult to make the filtering surface smooth and it is also difficult to evenly scrape off the solid component adhering or layered on the filtering surface. The use of the filtering cloth supporting drum and lattice prevent the realization of a wide filtering area, and it is further difficult to make the filtering machine or device itself compact.
In summary, the use of a soft belt shaped porous material as a filtering member for a separating apparatus may be often subjected to deformation of the filtering surface of the filtering member during the sucking operation and therefore a central core or like members is required for eliminating this defect, resulting in a structure which is complicated and not economical. In view of this and other points, it is necessary to select and develop materials to be used as a filtering material. It may be required in the conventional solid-liquid separator to completely remove the solid component by the use of a scraping member or other additional means. It may also be required to effectively reuse the original fluid which has been supplied one time on the filtering surface but not subjected to the filtering operation.
Furthermore, in the foregoing discussion, although there is disclosed examples in which unnecessary solid materials or components are removed from the solid-liquid mixture fluid, the description will of course be applicable to examples in which necessary solid materials and components are separated to obtain them.